| abstract |
The solvent is non-protonic and contains carbonyl gps., i.e. an aldehyde or ketone such as acetone, methyl ethyl ketone, acetaldehyde, butyraldehyde, etc. The polyamine and solvent are combined together at -5 degrees C to +150 degrees C/2 min-24hrs and a cold soln. of the polyisocyanate in the same solvent added at 0-25 degrees C such that resulting polyurea contains free amino gps. available for further reaction. The polyurea may be freed from solvent and cross-linked, e.g. with cross-linking agents, to form viscous insol. resins. Used as impregnants and binders for paper, textiles, metals, glass etc. |